Recently, in VTR, in order to accomplish a long-time recording, a method is employed wherein the tape transport speed is lowered during a recording to increase the recording density. This results in reduction in width of any one of recorded tracks. By way of example, the track width in a long-time recording mode in a 8-mm VTR is 10 .mu.m. In order for a reproducing head to accurately scan such narrow recorded tracks, a tracking control is required for controlling the position of a reproducing magnetic head relative to each of the recorded tracks by the use of a movable head.
In some of the VTRs, the use of an electric-mechanical transducing element is made to vary the mechanical heightwise position of the magnetic head to accomplish a noiseless reproduction not only during a normal reproduction in which reproduction is carried at the same tape transport speed V.sub.N as that during the recording, but also during any one of a still reproduction in which the scanning is carried out with the tape held still, a slow-motion reproduction in which the scanning is carried out at a tape transport speed which is lower than the tape transport speed V.sub.N and a double-speed reproduction in which the scanning is carried out at a tape transport speed which is higher than the tape transport speed V.sub.N.
Hereinafter, the noiseless reproduction with the use of the movable head will briefly be discussed.
FIG. 18 is a schematic diagram showing scanning traces of the head depicted during such a special reproduction as hereinbefore described. Since the tape transport speed during the normal reproduction is the same as that during the recording, the angle .theta..sub.N of inclination of each scanning trace on the tape is, as shown by the arrow 1802, equal to the angle .theta..sub.T of inclination of any one of the recorded tracks T and the reproducing head can accordingly scan any one of the recorded tracks accurately.
However, when a reproducing speed is changed from the tape transport speed V.sub.N and, for example, if the direction of movement of the tape is in a direction shown by the arrow 1805 with the tape moved at a three-fold speed, the direction of scan of the reproducing head on the tape will be such a direction as indicated by the arrow 1803, or such a direction as indicated by 1804 in the case of the still reproduction, and the angle of inclination thereof will become .theta..sub.3 or .theta..sub.0, respectively, which is different from the angle .theta..sub.T of inclination of the recorded track T.
Accordingly, in such a case, the reproducing head will scan while straddling a plurality of the recorded tracks and an image will be disturbed under the influence of noises. In view of this, if the reproducing head is fitted with an electric-mechanical transducing element such as a piezoelectric transducer or the like and a voltage proportional to the amount of deviation between the direction of scan, shown by the arrow 1802 in FIG. 18, during the normal reproduction and the direction of scan, shown by the arrows 1803 and 1804, during the reproduction which is accomplished at a different tape transport speed is supplied to the electric-mechanical transducing element, the magnetic head can accurately scan the recorded track T, resulting in reproduction of a noiseless reproduced image.
A method of recording and reproducing with the use of such an electric-mechanical transducing element is suggested in SMPTE Journal, December (1984), p.1134 to p.1137. According to this suggestion, the electric-mechanical transducing element is driven with the use of a control signal, indicative of the position of the tape, and an FG signal of a capstan, so that a still recording and a field or frame recording can be accomplished as defined by a format.
However, with this conventional construction, if the electric-mechanical transducing element such as a piezoelectric transducer has a deviation in both of the hysteresis characteristic and the driving sensitivity, there is a possibility that a deviation may occur from a track pattern of the format even if a control is effected to apply a predetermined value to a driving circuit for the electric-mechanical transducing element so that a predetermined applied voltage can be supplied to the electric-mechanical transducing element. Also, if an attempt is made to effect a recording with the magnetic head on the electric-mechanical transducing element during, for example, an insert edition to accomplish the recording in which a track curvature of the recorded track is taken into consideration, the presence of the deviation in the hysteresis characteristic as well as the driving sensitivity may result in that the scanning trace of the magnetic head will be different from the target recorded track. Consequently, there is a problem in that the recorded track pitches between the currently recorded tracks and the previously recorded tracks will vary from place to place and, at the joint such as formed during, for example, the insert edition, the previously recorded track may be erased.